OPINIONS: Rav Asi says that if a couple have not had children after ten years of marriage, Beis Din does not force them to get divorced. Rav Tachlifa in the name of Shmuel argues and says that Beis Din does force them to get divorced. (See Yevamos 64a.)
What is the Halachah?
(a) RASHI (Yevamos 65b, DH Hu and DH Hi) writes that Beis Din must force a man to divorce his wife (and marry someone else) in order to have him fulfill the Mitzvah of Piryah v'Rivyah. This is also the ruling of the RIF and the RAMBAM (Hilchos Ishus 15:7) who write that Beis Din compels him to divorce her even if Beis Din must use physical force. (The ROSH (6:15-16) adds that Beis Din also forces him to marry another wife, because otherwise there would be no point in forcing him to divorce the first one. Similarly, Beis Din is enjoined to force, at a certain point, a bachelor who refuses to get married.)
(b) TOSFOS (Yevamos 64a, DH Yotzi) and RABEINU CHANANEL (ibid.) rule, based on the YERUSHALMI (Kesuvos 11:7), that Beis Din does not force the man to divorce his wife. Rather, Beis Din tells him that he is obligated to divorce his wife and that if he does not, the people will be permitted to call him a sinner.
(a) Who exactly does the Gemara require to divorce his wife and marry another woman after ten years of childlessness?
1. The Poskim cite the Yerushalmi which states that the Gemara's ruling applies not only to one who had no children or who had stillborns, but even to one who had children but they died and he no longer has any living children (or grandchildren). He, too, must divorce his wife if ten years have passed and they have not had more children.
2. The Gemara here and the Mishnah in Yevamos state that this Halachah applies when ten years pass "without giving birth." The RAMBAN and other Rishonim infer from these words that if a man's wife bore him a single child, he is not required to divorce her, even though he has not fulfilled the Mitzvah of Piryah v'Rivyah with the birth of a single child. The REMA records this ruling as the Halachah in practice. The PISCHEI TESHUVAH adds in the name of the ME'IL TZEDAKAH (#93) that even if the wife is no longer capable of bearing children and they will never have a second child, Beis Din still does not force him to marry another wife.
(b) There are several opinions with regard to the practical application of this Halachah.
1. The SHULCHAN ARUCH (EH 154:10) cites the RIF and RAMBAM who rule that Beis Din forces the man to divorce his wife after ten years of childlessness. Other Poskim, however, limit -- or entirely eliminate -- this practice:
2. RASHI, the HAGAHOS MAIMONIYOS, and others rule that this Halachah applies only in Eretz Yisrael and not in Chutz la'Aretz (see Insights to Yevamos 64:1).
3. The Hagahos Maimoniyos (Hilchos Ishus 15:4) adds in the name of the AVI'ASAF that nowadays even in Eretz Yisrael Beis Din may not force a man to divorce his wife after ten years of childlessness. The Gemara in Bava Basra (60b) relates that the Chachamim considered enacting a prohibition against marriage when the nations began to persecute the Jewish people. They reasoned that it is better for the Jews to cause their own end by not having children than to be destroyed by their enemies. The Chachamim, however, decided against such an enactment on the grounds that it would have been too difficult for the people to observe. Nevertheless, the very proposition of such an enactment shows that nowadays Beis Din is not required to force a person to fulfill the Mitzvah of Piryah v'Rivyah.
4. The REMA (EH 154:10) concludes that nowadays it is not the practice of Beis Din to use force (in this matter and in any matters of Ishus). Should, however, the man himself voluntarily divorce his wife l'Chatchilah?
The PISCHEI TESHUVAH cites the SEFER BIGDEI KEHUNAH (#1) who rules that if a man's wife is G-d-fearing and they are happily married, they may remain married even l'Chatchilah and rely on the opinions which maintain that in Chutz la'Aretz one does not need to divorce his wife. He may also remain with his wife based on the logic that he does not know for certain that the source of the problem is his own inability to bear children (and thus divorcing her and marrying another will not help).
RAV MOSHE STERNBUCH shlit'a (TESHUVOS V'HANHAGOS 1:790) points out that this was the practice of many great Torah scholars who, unfortunately, were unable to have children. Rav Sternbuch adds that even when the man and his wife live in Eretz Yisrael, it is impossible to know for certain that it is not one's sins which cause him not to have children, as we are all so sullied with sin. (In his responsum, Rav Sternbuch describes a number of Segulos which he recommends for couples trying to have children.)